Semax is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2026-02-01. Numbers and descriptions here follow the published literature rather than marketing material.
Published research on this peptide originates mainly from Russian laboratories, and the wider international literature is comparatively thin. Studies have used rodent models of stroke, hypoxia, and memory tasks, with a smaller number of human trials reported. Reported outcomes include changes in attention and memory measures, along with effects on neurotrophic factor expression in some experiments. Small sample sizes, inconsistent dosing protocols, and limited independent replication are widely noted limitations, so the strength of the clinical evidence remains an open question.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. The first four residues correspond to the ACTH(4-10) fragment, while the terminal Pro-Gly-Pro extension was added to improve metabolic stability. Its molecular formula is C37H51N9O10S and its monoisotopic mass is approximately 813.9 Da. The compound is classified as a peptide research chemical and as a registered pharmaceutical product in Russia, but it does not hold marketing approval in the European Union or the United States. Naming conventions vary across supplier catalogs.
该化合物于二十世纪八十年代在俄罗斯被开发，相关工作由俄罗斯科学院分子遗传学研究所的研究团队主导。开发目标并非复制 ACTH 的完整激素活性，而是寻找保留其神经作用方向、同时去除促肾上腺皮质激素释放效应的短肽片段。研究记录显示，这一方向促成了多个相关短肽的合成与筛选，而 Semax 是其中被研究最广泛的一个。当地文献常以 Семакс 这一名称指代它。
研究兴趣主要集中在神经营养因子相关的路径上，包括脑源性神经营养因子与神经生长因子的表达变化。部分实验报告称在特定条件下观察到这些因子的水平上升，但具体信号通路和剂量依赖关系仍未完全厘清。多数公开数据来自细胞模型和动物实验，人体对照研究数量有限。因此，该化合物的作用机制在文献中属于活跃讨论，而非已经确立的定论。
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Seven-residue peptide |
| Molecular mass | 813.9 Da | Monoisotopic value |
| Appearance | White to off-white powder | Lyophilized form |
| Solubility | Freely soluble in water | Also soluble in saline and polar solvents |
| Storage (dry) | -20 °C or lower | Desiccated, protected from light |
Reported pharmacological work centers on neurotrophic signaling, including changes in BDNF and NGF expression in hippocampal tissue in animal models. Human data come largely from studies conducted in Russia, and how well those results generalize to other populations remains an open question. Regulatory status differs sharply by jurisdiction: Semax is a registered prescription medicine in Russia, while it holds no approved marketing status in the United States or the European Union. Outside such jurisdictions it is generally handled as a research chemical, which affects both documentation and quality expectations.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. It was developed as a fragment analog of adrenocorticotropic hormone, modeled specifically on the ACTH(4-10) region. The first four residues reproduce that fragment, while a Pro-Gly-Pro tripeptide is appended at the C-terminus. Work on the compound originated in Russia, where it entered clinical use as an intranasal preparation. Its sequence places it among short regulatory peptides studied for effects on the central nervous system rather than on the adrenal axis.
Laboratory descriptions of the material are consistent across suppliers. It appears as a white to off-white lyophilized powder that dissolves readily in water and in polar organic solvents such as dimethyl sulfoxide. Aqueous solutions are clear and colorless at low concentrations. Because the peptide contains methionine, oxidation at the sulfur atom is a recognized degradation pathway, and handling notes usually call for protected, desiccated storage. Reported purity for research-grade lots is generally above 95 percent as measured by reversed-phase high-performance liquid chromatography.
The compound is registered in Russia as a pharmaceutical product, most commonly formulated as a nasal solution, and has been used in that setting since the 1990s. Outside that jurisdiction it is generally handled as a research chemical rather than an approved medicine. Regulatory status therefore differs sharply between countries, and material sold internationally may not correspond to the Russian pharmaceutical formulation. Documentation with commercial samples is typically limited to a certificate of analysis covering purity and identity, not clinical status or local legal classification.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It is described in the literature as an analogue of the ACTH(4–10) fragment, a short N-terminal portion of adrenocorticotropic hormone that retains some neurotropic activity without the full hormonal effects of the parent peptide. The molecule carries a methionine residue at the N-terminus and two proline residues near the C-terminus, features that shape both its interactions with receptor systems and its chemical stability. The free peptide corresponds to the formula C37H51N9O10S and a molecular mass near 813.9 Da.
The compound was developed in the 1980s at the Institute of Molecular Genetics in Moscow, where it emerged from research on short ACTH fragments and their effects on the central nervous system. Russian pharmaceutical listings describe it as a nootropic and neuroprotective agent, most often formulated as nasal drops. It is not a marketed medicine in the United States or the European Union, and no pharmacopoeial monograph covers it. Consequently, most published clinical experience with the substance originates from a small number of research centres, mainly in Russia and neighbouring countries.
Semax is a synthetic seven-amino-acid peptide whose sequence extends the ACTH(4-10) fragment with a C-terminal proline-glycine-proline tripeptide. The commonly cited sequence is Met-Glu-His-Phe-Pro-Gly-Pro, giving a molecular formula near C37H51N9O10S and a molecular weight close to 813.9 g/mol. It belongs to the broader class of synthetic ACTH fragments studied for central nervous system effects rather than for adrenal steroid stimulation. In practice the material appears as a lyophilized white powder for laboratory work or as a dilute saline solution in clinical settings.
Development is attributed to researchers at the Institute of Molecular Genetics in Moscow during the early 1980s, building on earlier Soviet work with ACTH fragments. Russian regulatory approval followed for intranasal use, and the compound has remained commercially available there for decades. Most published human data originate from Russian and, later, some Eastern European clinical reports, which are not always accessible in English translation. Outside that region the material is generally handled as a research chemical rather than a licensed medicine.
Regulatory status differs sharply between jurisdictions. In Russia the peptide is registered as a prescription nasal preparation, while agencies such as the United States Food and Drug Administration have not approved it for any indication. Products sold elsewhere are typically labeled for laboratory research only, and such labels shift responsibility for safe handling to the purchaser. Because the same name covers pharmaceutical-grade nasal drops and bulk research powder, identity and purity documentation becomes the main practical concern when comparing sources.
Those who take it regularly at a higher dose (more than 2–3 g daily) are at much higher risk (3.6–3.7 times) of gastrointestinal bleeding and other bleeding events. Meta-analyses suggest that paracetamol may increase the risk of kidney impairment by 23% and kidney cancer by 28%. Paracetamol slightly but significantly increases blood pressure and heart rate. A review of available research has suggested that an increase in systolic blood pressure and increased risk of gastrointestinal bleeding associated with chronic paracetamol use shows a degree of dose dependence. The association between paracetamol use and asthma in children has been a matter of controversy. However, the most recent research suggests that there is no association, and that the frequency of asthma exacerbations in children after paracetamol is the same as after another frequently used pain killer, ibuprofen. In recommended doses, the side effects of paracetamol are mild to non-existent. In contrast to aspirin, it is not a blood thinner (and thus may be used in patients where bleeding is a concern), and it does not cause gastric irritation. Compared to Ibuprofen—which can have adverse effects that include diarrhea, vomiting, and abdominal pain—paracetamol is well tolerated with fewer side effects. Prolonged daily use may cause kidney or liver damage. Paracetamol is metabolized by the liver and is hepatotoxic; side effects may be more likely in chronic alcoholics or patients with liver damage.
== Structure == 50S, roughly equivalent to the 60S ribosomal subunit in eukaryotic cells, is the larger subunit of the 70S ribosome of prokaryotes. The 50S subunit is primarily composed of proteins but also contains single-stranded RNA known as ribosomal RNA (rRNA). rRNA forms secondary and tertiary structures to maintain the structure and carry out the catalytic functions of the ribosome. X-ray crystallography has yielded electron density maps allowing the structure of the 50S in Haloarcula marismortui (archaeon) to be determined to 2.4Å resolutionand of the 50S in the Deinococcus radiodurans (bacterium) to 3.3Å. The large ribosomal subunit (50S) is approximately twice as massive as the small ribosomal subunit (30S). The model of Hm 50S, determined in 2000 by Nenad Ban and colleagues in the laboratory of Thomas Steitz and the laboratory of Peter Moore, includes 2711 of the 2923 nucleotides of 23S rRNA, all 122 nucleotides of its 5S rRNA, and structure of 27 of its 31 proteins.
Increased thrombin inhibition requires the minimal heparin pentasaccharide plus at least an additional 13 monomeric units. This is thought to be due to a requirement that antithrombin and thrombin must bind to the same heparin chain adjacent to each other. This can be seen in the series of models shown in Figure 5. In the structures shown in Figure 5 the C-terminal portion (P' side) of the reactive site loop is in an extended conformation when compared with other un-activated or heparin activated antithrombin structures. The P' region of antithrombin is unusually long relative to the P' region of other serpins and in un-activated or heparin activated antithrombin structures forms a tightly hydrogen bonded β-turn. P' elongation occurs through the breaking of all hydrogen bonds involved in the β-turn. The hinge region of antithrombin in the Figure 5 complex could not be modelled due to its conformational flexibility, and amino acids P9-P14 are not seen in this structure. This conformational flexibility indicates an equilibrium may exist within the complex between a P14 P15 reactive site loop inserted antithrombin conformation and a P14 P15 reactive site loop expelled conformation. In support of this, analysis of the positioning of P15 Gly in the Figure 5 complex (labelled in model B) shows it to be inserted into beta sheet A (see model C).
== External links == Tobacco Etch Virus (Pepper Diseases) Archived 2010-08-27 at the Wayback Machine Tobacco Etch Virus (Tomato Diseases) Archived 2011-07-16 at the Wayback Machine Tobacco Etch Virus (DAS-ELISA) Archived 2016-04-17 at the Wayback Machine ICTVdB - The Universal Virus Database: Tobacco etch virus Family Groups - The Baltimore Method Archived 2000-01-15 at the Wayback Machine Descriptions of Plant Viruses (DPV)
Sources: en.wikipedia.org
Costunolide synthase (EC 1.14.14.150) is an enzyme with systematic name germacra-1(10),4,11(13)-trien-12-oate,NADPH:oxygen oxidoreductase (6alpha-hydroxylating). This enzyme catalyses the following chemical reaction
In 2022, keyboardist Andy Fletcher (a founding member of the UK band Depeche Mode) died unexpectedly from an aortic dissection at the age of 60. U.S. senator Lindsey Graham died in 2026 at the age of 71; the District of Columbia medical examiner's preliminary findings gave the cause of death as aortic dissection due to arteriosclerotic cardiovascular disease.
=== Cholesterol and hypertension === Daly and her colleagues did some of the earliest work relating diet to the health of the cardiac and circulatory systems. They investigated the impact of cholesterol, sugar, and other nutrients. She was the first to establish that hypertension was a precursor to atherosclerosis, and the first to identify a relationship between cholesterol and clogged arteries, an important discovery in understanding how heart attacks occur. She was especially interested in how hypertension affects the circulatory system. She showed that high cholesterol intake in diet led to clogged arteries, and that hypertension accelerated this effect. She studied the effects of diet on hypertension, and found that both cholesterol and sugar were related to hypertension. Investigating aging, she suggested that smooth muscle hypertrophy due to aging might have a causative role in hypertension and atherosclerosis. Daly was also an early investigator into the effects of cigarette smoke on the lungs and on hypertension.
represent the country at home and abroad appoint and recall heads of diplomatic and consular missions receive letters of credence and recall from foreign diplomatic representatives confer medals and other decorations promulgate laws passed by the Parliament call for parliamentary elections In 2003, the powers of the president were extended to include the right to chair the Council of Ministers and propose the composition of the Council of Ministers to the parliament, effectively merging the powers of the head of government into the office. However, although the president became de jure both head of state and head of government, his role was largely limited because all the institutions were indirectly elected by confederal parliament, which was itself elected by parliaments of member states.
==== United States ==== The first approved PSMA imaging agent was indium-111 (111In) capromab pendetide (branded Prostascint). It received Food and Drug Administration (FDA) approval in 1996. However, the agent had poor sensitivity and saw little widespread use. The first PET PSMA imaging agent, 68Ga-PSMA-11, was approved by the FDA in 2020. Listed indications include suspected metastasis prior to initial treatment, and recurrence of prostate cancer (based on elevated serum prostate-specific antigen (PSA) level). This was followed by two further 68Ga-PSMA-11 agents in 2021 and 2022 (branded Illucix and Locametz). Listed indications for Lucametz additionally includes selection of patients prior to 177Lu-PSMA radionuclide therapy. An 18F-PSMA agent (18F-DCFPyL) (branded Pylarify) was approved by the FDA in 2021. Indications are as for 68Ga-PSMA-11. Another 18F-PSMA agent (18F-rhPSMA-7.3) (branded Posluma) was approved by the FDA in 2023.
Sources: en.wikipedia.org
In 1976 South Africa saw settlement of the Rhodesian question as vital on several fronts: to cauterise the wound of the psychological blow … caused by her defeat in the Angolan conflict; to pre-empt possible Cuban intervention in Rhodesia and the possibility of South Africa being sucked into another Cold War regional conflict without the support and endorsement of the western powers In the latter 1970s, the militants had successfully put the economy of Rhodesia under significant pressure while the numbers of guerrillas in the country were steadily increasing. The government abandoned its early strategy of trying to defend the borders in favour of trying to defend key economic areas and lines of communication with South Africa, while the rest of the countryside became a patchwork of "no-go areas".
==== Mechanical properties ==== The mechanical properties of iron and its alloys are extremely relevant to their structural applications. Those properties can be evaluated in various ways, including the Brinell test, the Rockwell test, and the Vickers hardness test. The properties of pure iron are often used to calibrate measurements or to compare tests. However, the mechanical properties of iron are significantly affected by the sample's purity: pure, single crystals of iron are actually softer than aluminium, and the purest industrially produced iron (99.99%) has a hardness of 20–30 Brinell. Very pure iron (99.9%～99.999%) called electrolytic iron is industrially produced by electrolytic refining. An increase in the carbon content will cause a significant increase in the hardness and tensile strength of iron. Maximum hardness of 65 Rc is achieved with a 0.6% carbon content, although the alloy has low tensile strength. Because of the softness of iron, it is much easier to work with than its heavier congeners ruthenium and osmium.
== Signs and symptoms == Sydenham's chorea is characterized by the abrupt onset (sometimes within a few hours) of neurological symptoms, classically chorea, which are non-rhythmic, writhing or explosive involuntary movements. Usually all four limbs are affected, but there are cases reported where just one side of the body is affected (hemichorea). Typical chorea includes repeated wrist hyperextension, grimacing, and lip pouting. The fingers can move as if playing the piano. There may be tongue fasciculations ("bag of worms") and motor impersistence, for example, the "milkmaid sign" (grip strength fluctuates, as if hand milking a cow), or inability to sustain tongue protrusion (called jack-in-the-box tongue or serpentine tongue, as the tongue slides in and out of the mouth), or eye closure. There is usually a loss of fine motor control, which is particularly obvious in handwriting if the child is of school age. Speech is often affected (dysarthria), as is walking; legs will suddenly give way or flick out to one side, giving an irregular gait and the appearance of skipping or dancing. Underlying the abnormal movements is often low tone (hypotonia) which may not become obvious until treatment is started to suppress the chorea. The severity of the condition can vary from just some instability on walking and difficulty with handwriting, to the extreme of being wholly unable to walk, talk, or eat (chorea paralytica). Movements cease during sleep.
=== Osmotic pressure === Osmotic pressure is the pressure required to prevent a solvent from passing from a region of high concentration to a region of low concentration through a semipermeable membrane. When the concentration of dissolved materials or solute is higher inside the cell than it is outside, the cell is said to be in a hypotonic environment and water will flow into the cell.When the bacteria is placed in hypertonic solution, it causes plasmolysis or cell shrinking, similarly in hypotonic solution, bacteria undergoes plasmotysis or turgid state. This plasmolysis and plasmotysis kills bacteria because it causes change in osmotic pressure.
Sources: en.wikipedia.org
It is a synthetic peptide of seven amino acids. Its backbone corresponds to a fragment of adrenocorticotropic hormone extended at the carboxyl end. The material is distributed as a lyophilized solid for laboratory use.
The extension was introduced to slow enzymatic breakdown of the peptide in biological systems. Natural ACTH fragments are degraded rapidly by peptidases. Adding the tripeptide was intended to extend the window during which the molecule remains intact.
Most published work consists of animal experiments conducted in a small number of laboratories. Human data are limited in number and size. Whether the observed effects translate into reliable clinical benefit is still unresolved.
不是。Semax 是完全人工合成的七肽，自然界中没有对应的已知肽段。它的设计灵感来自促肾上腺皮质激素片段 ACTH(4-10)，但序列经过了替换和延长。